Date of Completion
Steven L. Suib
The microwave synthesis of heavily doped sodium tungsten bronze materials has been investigated. This solid state synthesis is more environmentally friendly than other syntheses typically used. The typical synthesis procedure involves heating the reagents to high temperatures for a long period of time, which requires a lot of energy. The microwave synthesis takes only 5-10 minutes, and needs 800-900 W of power, which uses much less energy. Even though there are clear benefits, the microwave synthesis has not previously been optimized and investigated in depth. The materials synthesized in this study were characterized with X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy-Dispersive X-Ray Spectroscopy (EDAX), Transmission Electron Microscopy (TEM), Raman Spectroscopy, and multiple conductivity tests. The gathered data showed which methods resulted in the materials with the cleanest XRD patterns, or highest conductivities. SEM and EDAX helped confirm that the sodium was incorporated into the bronze structure. The ideal reagent combination included sodium tungstate, tungsten trioxide, and tungsten metal powder. The materials with the highest sodium to tungsten ratio (0.80-0.95) were most conductive, and most often had a clean XRD pattern. The properties of the sodium tungsten bronze materials varied between samples, even when the same microwave procedure was carried out, which indicated that the microwave synthesis was not very predictable.
Murdzek, Jessica, "The Optimization of the Microwave Synthesis and Subsequent Characterization of Sodium Tungsten Bronze (NaxWO3) Materials" (2017). Honors Scholar Theses. 532.